1. Field of the Invention
This invention relates to dispensers, and more particularly to flexible dispensers that permit dispensing of material through deformation and displacing the dispensed material with fluid that enters an expansible bladder within the dispenser.
2. Prior Art
A dispenser is disclosed in U.S. Pat. No. 3,319,837 to Mueller, issued May 16, 1967, entitled xe2x80x9cDispensing Device.xe2x80x9d A bladder within a flexible container receives displacement fluid such as air that flows into the bladder after contents of the container have been dispensed by squeezing the container and then allowing the container to return to its original volume. The container employs one way valves to assure that displacement fluid only enters the bladder, in effect maintaining the contents adjacent the container so that the container is always xe2x80x9cfullxe2x80x9d until empty. A disadvantage of this dispenser is that the manner in which the bladder expands is not controlled, resulting in possible trapping of the contents remote from the outlet, which is then difficult to dispense. Another dispenser is disclosed in U.S. Pat. No. 4,239,132 to Mueller et al., issued Dec. 16, 1980, and entitled xe2x80x9cApparatus For Facilitating Inflow Through Closure Threads of Dispenser.xe2x80x9d That dispenser includes a tube in a flexible container and through which displacement fluid such as air flows to inflate the bladder and displace material dispensed from the container. That construction provides some, but only limited control of bladder expansion.
The present invention is directed to a flexible and resilient container, a support post preferably supported in the container, a cartridge disposed in the container and containing fluid material to be dispensed, the cartridge including an expansible bladder preferably connected to a collar member, the collar member being slidably disposed on the post, a first flow restrictor for allowing flow of air only from outside the container into an interior of the bladder, and a second flow restrictor for allowing flow of material only from within an interior portion of the container external to the bladder to outside the container.
More specifically, the collar member is connected to the bladder and is adapted for movement toward a fluid dispensing end portion of the container. The bladder sealingly surrounds the first flow restrictor. An end cap is fastened to the container for closing off an opening at a displacement fluid receiving end portion of the container. In a preferred aspect of the invention, the cartridge includes a piston which is connected to or formed integrally with the collar member. The piston is preferably formed of a flexible material and is adapted for movement in the container.
The cartridge is sealed at a fluid dispensing end portion to prevent the material that is filled into the cartridge from leaking out during shipping and handling. The cartridge is preferably cylindrical shaped. A xe2x80x9clowerxe2x80x9d section of the cartridge is folded into an xe2x80x9cupperxe2x80x9d section or body portion of the cartridge. The collar and the lower section of the cartridge (e.g., the bladder) are disposed in the upper section such that when the cartridge is filled with the material to be dispensed, the collar is located adjacent the bottom of the upper section and the bladder preferably forms a loop that extends from the collar member substantially halfway along the side wall of the upper section. It will be appreciated by one skilled in the art that relational terms such as xe2x80x9cupperxe2x80x9d and xe2x80x9clowerxe2x80x9d are used for improving understanding of the invention and should not be construed as necessary limitations thereof. The upper and lower sections of the cartridge may be formed of material having the same flexibility or thickness. Alternatively, to improve handling of the cartridge, the upper section of the cartridge may be formed of a less flexible or thicker material than the lower section of the cartridge.
The end cap is removably fastened to the container to provide an air tight seal of the cartridge in the container. The end cap is fastened, such as by threads, to the displacement fluid receiving end portion of the container. The first flow restrictor that allows only displacement fluid to enter the container and act upon the interior of the bladder, is preferably disposed in the end cap. The end cap may include a recess for receiving the post. A cutting element for breaking the seal of the cartridge may be supported in the container. A stop member that prevents axial movement of the support post, may also be supported in the container.
The first flow restrictor includes a first passageway through the container, preferably through the end cap, that communicates with the interior of the bladder, and a first check valve that cooperates with the first passageway. The structure of the second flow restrictor may be adapted to suit the viscosity of the fluid material to be dispensed from the container. When the fluid to be dispensed is sufficiently viscous, the second flow restrictor may be merely a dispensing passageway through the container that communicates with an interior portion of the container external to the bladder. In that case, the viscous material itself inhibits foreign material, including displacement fluid, from undesirably entering the container through the second passageway. On the other hand, when a less viscous material is to be dispensed from the container, the second flow restrictor preferably includes a second check valve cooperating with the second passageway to inhibit foreign material from undesirably entering the container through the second passageway.
A preferred embodiment of the invention is directed to a cartridge for refilling the fluid dispenser. The cartridge includes a body portion and the expansible bladder extending therefrom. The collar member is connected to the bladder. The support post may be supported by the cartridge before it is loaded into the container. Alternatively, the post may be supported in the container rather than in the cartridge, or inserted into the bottom of the sealed cartridge, in which cases in addition to the seal at the fluid discharge end of the cartridge a seal may be disposed over an aperture in the collar member that receives the support post.
When it is desired to dispense material, the container and, in turn, the cartridge are flexed along their side walls. Internal pressure within the container forces the material through the second flow restrictor and out of the container through the second passageway. When flexing pressure on the container is removed, the side walls of the container and cartridge return to their original shape. The second check valve prevents displacement fluid such as air from entering the container through the dispensing passageway and ambient pressure outside the container overcomes the bias of the first check valve and ambient fluid (e.g., air) enters the bladder. Frictional forces between, for example, the piston and the post, resist the movement of the piston along the post. Displacement fluid that has entered the bladder then flows past the piston into the loop of the bladder, and initially inflates the loop of the bladder and urges it toward the second passageway, maintaining the loop above the piston. The forces of the displacement fluid active within the bladder and on the piston continually maintain the piston adjacent the material to be dispensed.
With the above arrangements, the loop of the bladder, being positioned above the piston as the bladder expands, avoids random expansion and entanglement of the bladder and formation of pockets of material in the container, trapped alongside by the bladder, rather than displaced toward the dispensing passageway. Movement of the piston toward the second passageway neatly controls the bladder expansion and decreases the size of the loop as the material in the container is depleted. This assures not only that the dispenser is in effect always xe2x80x9cfull,xe2x80x9d regardless of the orientation of the container, but also that essentially the entire contents can be effectively dispensed.
The container thus is divided into two sectionsxe2x80x94a section of fluid material to be dispensed and a section of displacement air or other fluid. The respective volumes of these two sections vary inversely as the cartridge, which is originally full of the material to be dispensed, is emptied through use.
The dispenser of the invention offers numerous advantages. The cartridge enables the dispenser to be conveniently and efficiently refilled. To refill the dispenser, the end cap is removed and the spent cartridge is moved out of the container. The refill cartridge is inserted into the container with or without its seal being broken. The seal at the dispensing end of the refill cartridge is broken at some point in a manner effective to enable discharge of the contents. The post, which may be carried by the cartridge, supported in the container, or inserted from the bottom of the sealed container, is positioned inside the container and/or inside the cartridge. The end cap is fastened to the displacement fluid end portion of the container, thereby completing the refill procedure.
Another advantage is that the design of the dispenser facilitates commercial use such as in applications where frequent refilling is necessary as in applying caulk or glue in carpentry, as well as with automation equipment in which the container may be kept in a fixed position by a support member and only the cartridge is moved during refilling. In addition to the advantageous refillable design of the invention, the dispenser prevents exposure of the fluid material from air or other fluid outside the container. The dispenser also enables an even or generally constant discharge of material, and is also usable with conventional metering devices and applicators. The dispenser may be utilized in various orientations, even so as to discharge fluid material vertically upward. The dispenser is able to efficiently discharge fluid material of a variety of viscosities from thick to watery. Examples of fluid materials that may be dispensed in accordance with the present invention include paints, caulks, soaps, and fluids utilized in the semiconductor industry, to name a few.
Other embodiments of the dispenser of the invention are contemplated to provide particular features and structural variants of the basic elements. The specific embodiments referred to as well as possible variations and the various features and advantages of the invention will become better understood from the detailed description that follows, when considered in connection with the accompanying drawings.